CMDs of the bright MS and BHeB stars in Leo A. Panel a: F814W versus F475W − F814W diagram (ACS). Panel b: I versus B − I diagram (Suprime-Cam). The two parallel blue dashed lines confine BHeB stars (colour-coded by age) for which individual ages were determined by interpolation between isochrones of various ages and metallicities. The BHeB stars located out of the valid age determination region have ages estimated only approximately and are marked by open (colour-coded by age) circles. MS stars are marked by violet dots. The isochrones of the same ages as in Fig. 1a and of two metallicities, that is Z = 0.0001 (dashed black lines) and Z = 0.0015 (solid black lines), are plotted for reference. The isochrone of 320 Myr age and of Z = 0.0001 metallicity (thick solid blue lines in both panels) marks the lower limit for BHeB star selection.